What Is Justice?

Question

What is justice, and why has it been the central question of political philosophy since Plato? The question arises because every society distributes benefits and burdens, punishes wrongdoing, and claims authority — and every such act raises the question of whether it is just. The philosophy of justice is the systematic attempt to answer this question.

Quick Answer

Justice is the moral standard for evaluating the basic structure of society. It concerns what each person is owed — their rights, their share of goods, their treatment under law. The major theories include Plato's harmony-based account, Aristotle's distributive-corrective distinction, John Rawls's justice-as-fairness, Robert Nozick's entitlement theory, and the utilitarian, communitarian, and capability-based alternatives. These theories disagree on nearly every substantive question, but they share the conviction that justice is not merely a matter of convention or power.

Historical Wisdom

The inquiry into justice begins with Plato's Republic, which defines justice as each part doing its own work — the rational part ruling the spirited and appetitive parts in the soul, and the philosopher-kings ruling the producers and guardians in the city. Justice, for Plato, is psychic and social harmony. Aristotle refined this into a more practical framework: distributive justice concerns the allocation of honors and goods according to merit; corrective justice restores balance when wrongdoing occurs. The medieval tradition, through Augustine and Aquinas, integrated justice with theological virtue. The modern era, beginning with Hobbes, reframed justice around contract and consent. The twentieth century saw the most concentrated period of philosophical work on justice, led by John Rawls, whose A Theory of Justice (1971) revived normative political philosophy and set the terms of debate for the next fifty years.

Philosophical Perspectives

John Rawls's justice-as-fairness proposes that the principles of justice are those that free and rational persons would accept in an original position of equality — behind a veil of ignorance where no one knows their place in society. From this standpoint, Rawls argues, they would choose two principles: equal basic liberties, and social and economic inequalities arranged so that they are attached to offices open to all and benefit the least advantaged (the difference principle). Justice, for Rawls, is about fairness in the terms of social cooperation.

Robert Nozick's libertarian reply in Anarchy, State, and Utopia (1974) rejects patterned theories of justice. If people are entitled to what they have acquired justly, Nozick argues, then any redistribution is a violation of rights. Justice is historical, not end-state: what matters is how holdings came about, not how they are arranged.

The egalitarian tradition challenges both Rawls and Nozick from the left. Critics argue that Rawls's difference principle does not go far enough, while Nozick's starting point — the legitimacy of original acquisition — is deeply problematic. The capabilities approach, developed by Amartya Sen and Martha Nussbaum, shifts the focus from the distribution of goods to the distribution of capabilities to flourish. The communitarian critique, advanced by Michael Sandel, Charles Taylor, and Alasdair MacIntyre, argues that justice cannot be detached from the shared understandings of particular communities.

Lessons From Thinkers

From Plato: justice is not merely a set of rules but a condition of harmony in the soul and society. From Aristotle: different contexts require different principles of justice. From Rawls: the fairest principles are those that no one could exploit. From Nozick: any theory of justice must take liberty seriously. From the egalitarians: the distribution of natural and social advantages is morally arbitrary and must be addressed. From Sen and Nussbaum: what matters is not just what people have but what they can do and be. And from the communitarians: justice is always justice for a particular community with its own traditions and understandings.

Practical Application

Justice is not merely an abstract ideal. It structures every debate about taxation, healthcare, education, criminal punishment, and social welfare. When we argue about whether the rich should pay more taxes, we are arguing about distributive justice. When we debate the fairness of a criminal sentence, we are arguing about retributive justice. When we ask whether a law is legitimate, we are asking about justice. The philosophical question — what is justice? — is therefore unavoidable in political life. The answer we give determines the kind of society we build.